public class Example3_6 {
  public static void main(String args[]){
    double sum = 0,item=1;
    int i=1,n=20;
    while(i<=n){
	sum=sum+item;
	i=i+1;
	item = item*(1.0/i);
    }
    System.out.println("sum="+sum);
  }
}
